It sounds like your sit bones are narrower than mine. I rode a Brooks Finesse -177 mm - for several years before it finally dawned on me that it was too wide and the cause of my shoulder rocking and saddle sores. So going with a regular Brooks B17 sounds like a bad idea to me.
I do love my Selle Italia SLK Lady Gel Flow and will buy yours from you if you still have it.
Competitive Cyclist does do a saddle demo program. Most of the saddles in it are men's. But by riding each of them in the trainer and taking careful notes about how each felt, I was able to figure out that the Selle Italia SLK Lady Gel Flow was the saddle I wanted from how they described each demo saddle on their website. You might give that a try.